The modern pentathlon has been cut from five events to four in a bid to boost the sport's popularity and keep it on the Olympic program.
The International Modern Pentathlon Union (UIPM) voted to combine pistol shooting and running into one discipline to create a shorter and more dynamic event.
UIPM President Klaus Schormann, described the recent decision at the federation's annual congress in Guatemala as "one of the biggest in the history of modern pentathlon.
He says he hopes the new format, which takes effect on January 1, will strengthen the sport's position in the Olympics.
Modern pentathlon has been criticised in recent years as lacking true international appeal and being dominated by athletes from eastern Europe.
It has featured in the Olympics since 1912 after being designed by Baron Pierre de Coubertin, founder of the modern games, to test an ideal soldier's skills.
Competitors must shoot an air pistol, fence, swim for 200 metres, ride a horse that is unknown to them over a showjumping course and run 3,000 metres.
Shooting and running will now be combined in a fourth and final discipline.
